Antenna device

1. An antenna device to be inserted in a memory card slot of an electronic device, comprising: an insulating layer, an antenna element formed on one surface of the insulating layer, and a ground element formed on the other surface of the insulating layer, the antenna element and the ground element being formed such that at least a part of the antenna element and at least a part of the ground element protrude from the memory card slot of the electronic device when the antenna device is inserted in the memory card slot, respectively; and a ground pattern formed to be extend in a plane which is parallel to the surfaces of the insulating layer and electrically connected to at least the ground element.

2. The antenna device according to claim 1 , wherein the antenna element includes a first linear portion and the ground element includes a second linear portion provided to overlap the first linear portion of the antenna element in a plan view, and the antenna element and the ground element are formed such that at least a part of the first linear portion and at least a part of the second linear portion protrude from the memory card slot of the electronic device when the antenna device is inserted in the memory card slot, respectively.

3. The antenna device according to claim 2 , wherein the first linear portion and the second linear portion extend in a first direction, respectively, the antenna element further includes a power supply portion for being applied with a voltage connected to the first linear portion and extending in a second direction substantially perpendicular to the first direction, and a first ground portion for being grounded connected to an end of the first linear portion to be extended in the second direction, and the ground element further includes a stub portion connected to the second linear portion and extending in the second direction to overlap the power supply portion of the antenna element in a plan view a second ground portion for being grounded connected to an end of the second linear portion and extending in the second direction to overlap the first ground portion of the antenna element.

4. The antenna device according to claim 2 , wherein the first linear portion and the second linear portion extend in a first direction, respectively, the antenna element further includes a power supply portion for being applied with a voltage connected to the first linear portion and extending in a second direction substantially perpendicular to the first direction, and the ground element further includes a ground portion for being grounded connected to the second linear portion and extending in the second direction to overlap the power supply portion of the antenna element in a plan view.

5. The antenna device according to claim 2 , wherein the ground pattern is formed not to overlap the first linear portion of the antenna element and a distance between the first linear portion and the ground pattern is less than or equal to 0.05λ (where “λ” is a wavelength of a voltage), in a plan view.

6. The antenna device according to claim 1 , wherein the antenna element and the ground element are substantially symmetrically formed from each other while interposing the insulating layer therebetween at substantially the same position in a plane view.

7. The antenna device according to claim 2 , wherein the insulating layer includes plural layers, the antenna element further includes a third linear portion electrically connected to the first linear portion and formed in a different layer from the first linear portion, and the ground element further includes a fourth linear portion electrically connected to the second linear portion and formed in a different layer from the first linear portion, the second linear portion, and the third linear portion to overlap the third linear portion of the antenna element in a plan view.

8. The antenna device according to claim 1 , wherein the antenna device is used for a frequency band between 2.4 GHz to 2.5 GHz.

9. The antenna device according to claim 1 , wherein the antenna device is used for Wireless Local Area Networks or Bluetooth.

10. The antenna device according to claim 1 , further comprising: a housing that covers the insulating layer, the antenna element, and the ground element; and a metal layer provided at a surface of the housing.

11. The antenna device according to claim 3 , wherein the first ground portion of the antenna element and the second ground portion of the ground element are electrically connected to the ground pattern.